The present invention relates to an input device. Usually, such input devices are named xe2x80x9ccomputer mousexe2x80x9d. Particularly, it is referred to an input device for a computer where the input device is designed to be controlled by groups of fine motor muscles. The invention also relates to a grip arrangement.
Usually, a traditional input device or computer mouse is formed by a device for detecting movements, which device is enclosed in a shell. Generally, a such device for detecting movements comprises a ball enclosed within the shell where the movement of the input device in relation to a support pad is registered through that the movements of said ball in relation to the support pad are decoded. In other known input devices optical devices for detecting movements are used which have the disadvantage of solely being able to detect movement in relation to support pads specially designed for the movement detection device.
According to a second known technical solution, the input device comprises a ball which is facing the user and designed to be directly controlled by the user through that the ball is rotated by the user""s fingers.
A problem with the above mentioned input devices is that the user is forced to perform static work with the muscles in that the forearm is pronated to an end position. Pronation means the arm""s rotation of the forearm with the thumb side in inward position and the palm in outward position. This is done by rotating the bone of the forearm around its longitudinal axis. Except for the pronation, known technics causes unnecessary static ulnar deviation and frequently also extension in the wrist itself.
Further, by for instance EP 501 906, it is known an input device in the form of a so called joystick, where the movement of a grip arrangement is decoded for generating a control signal to a computer. When using a joystick the grip arrangement is rotated around a pivot point which is situated at or in connection to the mounting of the grip arrangement into the housing of the input device. This means that manoeuvring of the grip arrangement during some movements will be controlled with the gross motor muscles of the forearm, instead of the fine motor muscles of the fingers.
Furthermore, the movement of the grip arrangement in a joystick is decoded relative the input device itself. This means that the input device must be attached to a support in a torsionally rigid way, alternatively be supported by a user""s both hands to operate satisfactorily.
To achieve input devices which allow handling by fine motor muscles, there have been proposed input devices in the form of a pen, which movements are decoded in relation to a drawing table. A disadvantage with this solution is that a special drawing table is needed and that the drawing table exhibits fixed positions. Thus, it is not the relative movement of the pen in relation to the drawing table that is decoded, but the position of the pen on the drawing table.
Moreover, it is known an input device in the form of a pen which supports a ball in the point of the pen and where the movement of the ball in relation to the pen is decoded. This pen presents a number of disadvantages. Partly, the pen must be held in a fixed angle to get the ball rolling, and partly there is no given orientation of the pen which means that divergence between the decoded movement and the performed movement can easily occur. In the example of rotating the pen 90xc2x0, a vertical movement of the pen can be apprehended by the computer as a horizontal movement. Furthermore, there is no simple form conformity between movements of the pen and decoded movement. In the example of transporting the pen along a support pad with a conical pendulum movement, the movement will be decoded as a straight line. The reason for this is that the angle of the pen is continuously changed during the pendulum whereby the movement of the ball in relation to the pen is constant. For instance this means that if a C is input with a conical pendulum, which is very common when a person writes and uses the fingers"" fine motor muscles, this C will be interpreted as an I by the computer.
To be able to use this pen correctly, the shaft must be held in a constant angle, which means that the pen will be controlled with the gross motor muscles of the forearm, instead of the fine motor muscles of the hand.
One object of the invention is to provide an input device for a computer where the risk of repetitive strain injuries is reduced and where an increased input precision is allowed. A second object of the invention is to provide an input device where the orientation of the input device can easily be visually determined by a user. A third object of the invention is to provide a simple representation between a performed movement observed by the user and movement decoded by the means for detecting movements.
By adding a protrusion comprising a torsionally rigid, flexible joint to a support element in the input device, where said support element is designed to be controlled of a user via said torsionally rigid, flexible joint, it is made possible to handle the input device with the fine motor muscles in the user""s hands. Furthermore, the decoded movement corresponds to the movement that the support element performs in relation to the support pad, since the torsionally rigid, flexible joint compensates for angle adjustments between the protrusion and the element.